Our objective is to develop a Streptavidin Macromolecular Adaptor (SAMA) enabling the controlled assembly of streptavidin-linked protein conjugates for nanotechnology, biomaterials and sensor applications. Streptavidin (SAV) is a tetrameric protein molecule of MW 60,000 with D2 symmetry that has 4 high-affinity binding sites for the vitamin biotin. Owing to the high stability of the streptavidin-biotin complex, coupled with the ability to biotinylate proteins through directed chemical modification, streptavidin has found wide use in biotechnology applications and has also been a key building block in protein-based nanotechnology. In many applications where streptavidin-biotin interactions are used, the quality and homogeneity of the resulting product is limited owing to lack of control over the macromolecular conjugation and assembly process. The present proposal describes the development of a Streptavidin Macromolecular Adaptor (SAMA), based on an engineered form of a thermostable dimeric protein MJ0557. SAMA is envisioned to effectively function both as an immobilization agent and as a reversible protecting group providing key advantages known from solid-phase chemical synthesis: 1) geometrical control of reactivity, 2) potential for specific immobilization of a growing molecular assembly, 3) ability to drive reaction equilibria to completion using mass action, and 4) greatly facilitated ability to purify reaction products from reagents. The specific aims of the project involve the detailed design, expression and biophysical characterization of SAMA and the SAV:SAMA complex. We intend to make the SAV:SAMA complex widely available to the biomedical, biotechnology and nanofabrication communities through web-based sales and distribution. We believe that the general availability of this SAMA will facilitate the development of a new generation of functional nanodevices, biosensors, and biomaterials, that in turn constitute new approaches for disease diagnostics and replacement materials for skin, bones and other tissues. We believe that the general availability of a molecule to direct the controlled synthesis of streptavidin- containing assemblies will tremendously facilitate the development of a new generation of functional nanodevices, biosensors, and biomaterials that in turn constitute new approaches for disease diagnostics and replacement materials for skin, bones and other tissues. [unreadable] [unreadable] [unreadable]